Thermal Head Section - Panasonic KX-F900 Service Manual

I...... KxFgo0-I
3-13. THERMAL HEAD SECTION
I
Is the voltage at pin 8 of CN251.
(Analog Board) 0-1 V? (When copying)
I YES
Is the voltage at pins
5,6 of CN301 23~24 V? (Power unit )
YES
Is the amplitude at
pins 1, 4-7 of CN11
4N5 Vp-p?
NO
YES
Is the amplitude at pins
1~3 of CN 11 4~5 Vp-p?
NO
YES
Check the cable of CN11
and CN301. (Power unit)
OK
Replace thermal head.
NO
Check switching power
supply section.
(Refer to page 72)
I s the voltage at pin 119
of IC1 4-5 V? (Digital
Board)
YES
Checkthe solder at pin
119 of ICl or pin 8 of
I CN251.
NO
_r
Take out CN11 and check the
amplitude again.
NG
OK
1
Check the solde at pins
22, 25-28 of IC1 or re-
place IC1. (Digital Board)
Check the voltage at pin
38 of IC1,3V (0%) >V__2V
(65%) about 2.6V (25%).
NG
OK
I ,
Check IC1. J
Take out CN11 and
check the amplitude
again.
I
NG
Check the solder at pins--/7
/
23, 24 of IC1.
Check R47, R48, R49,
C37, C38 and C39.
Replace the thermal
head.
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